add missing *_unlocked and wcsftime_l prototypes to wchar.h

these functions had been implemented, but prototypes were not made available

include/wchar.h

@@ -136,6 +136,21 @@ size_t wcsftime (wchar_t *__restrict, size_t, const wchar_t *__restrict, const s
 
 #undef iswdigit
 
+#if defined(_GNU_SOURCE)
+wint_t fgetwc_unlocked (FILE *);
+wint_t getwc_unlocked (FILE *);
+wint_t getwchar_unlocked (void);
+wint_t fputwc_unlocked (wchar_t, FILE *);
+wint_t putwc_unlocked (wchar_t, FILE *);
+wint_t putwchar_unlocked (wchar_t);
+wchar_t *fgetws_unlocked (wchar_t *__restrict, int, FILE *__restrict);
+int fputws_unlocked (const wchar_t *__restrict, FILE *__restrict);
+#endif
+
+#if defined(_GNU_SOURCE) || defined(_BSD_SOURCE)
+size_t wcsftime_l (wchar_t *__restrict, size_t, const wchar_t *__restrict, const struct tm *__restrict, locale_t);
+#endif
+
 #if defined(_POSIX_SOURCE) || defined(_POSIX_C_SOURCE) \
  || defined(_XOPEN_SOURCE) || defined(_GNU_SOURCE)  || defined(_BSD_SOURCE)
 FILE *open_wmemstream(wchar_t **, size_t *);